Yes, but it depends on what type of metal/aluminum mix they use. Regardless of what material they use, the structure weakens internally(think of bending a paper clip back and forth until it breaks). Since the wheels are supposed to be hard and hold up to a lot of pressure, I doubt it can bend many times.
It is called metal fatigue and it is cumulative effects. Even if they heat up the wheel to reshape it, it won't be the same.
I don't think it's a big deal if it's only once. But it is a big deal 2 or more times. However, note that after you bent it the first time, it takes less impact to bend the wheel again.
http://www.epi-eng.com/mechanical_en..._in_metals.htm